An Evaluation of the Cutting Efficiency of a Reciprocating Device with Ni-Ti File: Effect of Canal Shaping by RECIPROC Direct

Abstract

 Objective: A Reciproc nickel-titanium (Ni-Ti) file was designed specifically for preparing root canals with only one file under reciprocating motion. Although Reciproc is used to form a root canal with the X Smart Plus drive system, a Reciproc-specific handpiece (RECIPROC Direct) that can be connected to a dental unit was developed. The purpose of this study was to clarify the relationship between the rotational speed and transportation of the root canal using RECIPROC Direct. This study aimed to compare the cutting effect of Reciproc due to the difference in driving system between RECIPROC Direct and X Smart Plus.

 Materials and methods: Sixty simulated resin block canals with angle of curvature ranging 30°were divided according to the Ni-Ti driving system used for canal preparation into three groups of 20 samples each: experiment group 1 (EX1: RECIPROC 20,000 rpm), experiment group 2 (EX2: RECIPROC 15,000 rpm) with different rotational speed, and X Smart Plus as a control group. The preparation time was recorded, and all canals were scanned using an Olympus SZX16 and digital camera DP71 system before and after instrumentation to evaluate canal wall and canal central axis transportation at 1, 2, 3, 5 and 8 mm from the apex. The significance level was set at p<0.05.

 Results: Analysis of root canal wall displacement of the experimental group and the control group showed that the amount of displacement on the inner side in EX1 increased compared to that in the control group and the amount of displacement on the outer side decreased. On the other hand, in EX2, the amount of displacement on the inner side decreased and the amount of displacement on the outer side were the same, as compared with the control group. As a result of measuring the central axis transportation, EX1 was transported to the inner side, but in EX2, the transportation amount was small. The root canal formation time in EX 1 was 34.4±3.8 s, in EX 2 was 55.9±8.4 s, and in the control group was 44.6±3.8 s.

 Conclusion: As a result of comparing the cutting effects of Reciproc using RECIPROC Direct and X Smart Plus, it was shown that RECIPROC Direct influences the root canal morphology due to the difference in rotational speed. It was concluded that root canal formation of Reciproc using RECIPROC Direct maintains the anatomical root canal morphology by setting the rotational speed at 15,000 rpm.